Variable speed transmission

ABSTRACT

A variable speed transmission comprising outer and inner rotatable members mounted for rotation about first and second rotational axes, respectively, at least first and second one-way clutches mounted on the inner rotatable member, and first and second drive elements attached to the first and second clutches, respectively, and to the outer member so that rotation of one of the rotatable members about its rotational axis causes the drive elements to rotate the other of the rotatable members about its rotational axis. The radial spacing between the rotational axes can be adjusted to vary the drive ratio.

BACKGROUND OF THE INVENTION

Variable speed transmissions are used to transmit power at selectivelyvariable ratios. One class of variable speed transmission includes aninner rotatable member and an outer rotatable member drivingly coupledby a drive element. Rotation of one of the rotatable members drives theother rotatable member through the drive element.

Some prior art variable speed transmissions of this type are verycomplex as evidenced by Herman U.S. Pat. No. 1,807,035. Others use acomplex arrangement of planatary gears as evidenced by Green U.S. Pat.No. 741,904 and Hayden U.S. Pat. No. 977,449.

In the variable speed transmission disclosed in Mitchell U.S. Pat. No.736,129, ratio change is obtained by displacing the inner rotatablemember linearly relative to the outer rotatable member. This changes theradial spacing between the axes of rotation of the inner and outerrotatable members to in turn change the ratio. Although radiallydisplacing the axes of rotation is a desirable way to obtain ratiochange, relative linear movement of the rotatable members is notdesirable for all applications.

The variable speed transmission of the Mitchell patent used one-wayclutches around the periphery of the outer rotatable member to form adriving connection between the drive element and the outer rotatablemember. The use of the one-way clutches at the periphery of the outermember is fraught with disadvantages. For example, under high speedoperation, centrifugal force would act on the one-way clutches and pushthem against the outer rotatable member to create relatively highfriction. This type of one-way clutch tends to collect grit which inturn causes friction and high wear.

One way clutches of the type shown in the Mitchell patent require veryhard, inflexible surfaces for proper operation. In this prior artconstruction, the one-way clutches operate in a groove formed at theperiphery of the outer rotatable member. A primary problem with thisconstruction is that the walls of the groove must be very rigid andaccurately formed in order for the one-way clutches to operatesatisfactorily.

SUMMARY OF THE INVENTION

The present invention eliminates the problems noted above resulting fromlocating the one-way clutches at the periphery of the outer rotatablemember. With this invention, the one-way clutches are mounted on theinner rotatable member and are concentric therewith. This eliminates theneed for the annular groove in the outer rotatable member and theaccompanying necessity for hard surfaces on this groove. Furthermore,locating the one-way clutches on the inner rotatable member increasesthe torque capacity of the transmission and reduces friction. Inaddition, the type of one-way clutch suitable for mounting on the innerrotatable member tends to be self-cleaning, and the problems noted abovecaused by centrifugal force are minimized.

The drive element between the inner and outer rotatable members may takedifferent forms. For example, the drive element may include a rigidlink. The rigid link has the advantage of permitting high speedoperation and it can be used to drive either the inner or outerrotatable member. In addition, it minimizes the number of partsrequired.

The present invention teaches that, when the inner member is the drivemember, the drive ratio of a variable speed transmission of this type isapproximately 1:1/1-X where X equals A/R and A is the displacement ofthe axis of rotation of the inner member from the axis of rotation ofthe outer member and R is the distance between the axis of rotation ofthe inner member and the center of the location of attachment of thedrive element to the inner member. This formula can be used when A isless than R. Accordingly, to maximize the drive ratio and to obtain thegreatest ratio change for an increment of relative displacement betweenthe rotational axes of the rotatable members, the R dimension should beminimized. To accomplish this, the drive element may take the form of arigid link circumscribing an eccentric which in turn is mounted on theone-way clutch. A bearing is provided between the eccentric and therigid link to allow relative movement therebetween. This constructionminimizes the R dimension to thereby achieve the advantages noted above.

The present invention also teaches that the drive element may take theform of a flexible element. The flexible element may be a cable affixedto the outer and inner rotatable members or a chain drivingly coupled toa sprocket mounted on the one-way clutch. In either event, tensionshould be maintained on the flexible drive element by a spring or othersuitable means. Because a flexible drive element requires less spacethan a rigid link, it is possible to displace the rotational axes of therotational members' greater amounts than with a rigid link to therebyachieve substantial drive ratio changes. In addition, the surface of theone-way clutch contacted by the flexible drive element can be contouredto tailor the drive ratio to the angular position of the inner rotatablemember about its rotational axis.

To obtain a ratio change either or both of the inner and outer rotatablemembers may be moved relative to a fixed supporting structure such as ahousing. An optional feature of the present invention is mounting one ofthe rotatable members for pivotal movement about a third axis radiallydisplaced from the first and second rotational axes. By moving therotatable members so mounted along a path about a third axis, therelative locations of the first and second rotational axes is changed toprovide a ratio change. For some installations, this pivotal motion toobtain ratio change is simpler and otherwise superior to moving of therotatable members linearly to obtain ratio change.

After the relative position of the first and second rotational axes hasbeen selected, it is necessary to maintain this relationship duringoperation of the transmission. With the present invention, this isadvantageously accomplished by releasable detent means. Such detentmeans includes cam means responsive to the operator of the transmissiontending to move the rotatable members to change the relative positionsof the rotational axes for camming the detent to a releasing position toallow such ratio change to occur.

The inner and outer rotatable members may be coupled by one or moredrive elements. If only one drive element is utilized, the output of thetransmission will inherently be nonlinear unless other means areemployed to obtain a linear output. To approach a linear output, thenumber of drive elements and associated one-way clutches can beincreased. The one-way clutches can advantageously be arranged in anaxially extending row along the inner rotatable member.

With the present invention, either the inner or outer rotatable membersmay be used as the drive or driven member provided that the one-wayclutches are appropriately set. However, the drive ratio for a givenpositioning of the first and second rotational axes will not be the samewhen the inner member is the driven member as when it is the drivemember. For example, a drive ratio of 1 to 10 may be obtained when theinner member is the drive member and a ratio of 1 to 1.9 may be obtainedfor the same relative positions of the first and second rotational axeswhen the inner rotatable member is the driven member.

In use, each of the one way clutches is in a driving mode during aportion of the cycle and this tends to provide output pulses for drivingthe driven member. Another distinction between the present invention andthe device of the Mitchell patent is that with this invention the numberof such output pulses is a function of the angular velocity of the outerrotatable member whereas with the Mitchell device the number of outputpulses is a function of the angular velocity of the inner member. Thus,a greater number of output pulses for a given ratio and number of driveelements, and hence a more even output, is obtained with the presentinvention when the inner rotatable member is used as the driving member.For some applications the use of the inner rotatable member as thedriving member is the only practical arrangement.

Another feature of this invention is that two or more of thetransmission units, each of which includes inner and outer rotatablemembers, can be interconnected to form the transmission. Becausedifferent drive ratios are obtained depending upon whether the innerrotatable member is driving or being driven, the overall maximum ratioof the transmission can be varied by the manner in which thetransmission units are interconnected. For example, for a maximum ratiochange, the transmission unit should be coupled so that the inner memberis the drive member for both transmission units and for a minimumoverall ratio, the outer member should be the drive member for bothtransmission units. For an intermediate overall maximum ratio, eitherthe inner or the outer member could be the drive member for bothtransmission units.

The invention can best be understood by reference to the followingdescription taken in connection with the accompanying illustrativedrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of a variable speed transmissionconstructed in accordance with the teachings of this invention with theouter cover removed. FIG. 1 is taken generally along line 1--1 of FIG.2.

FIG. 1a is a fragmentary sectional view of one form of releasable detentmeans constructed in accordance with the teachings of this invention.

FIG. 2 is a sectional view taken generally along line 2--2 of FIG. 1.

FIG. 3 is a simplified sectional view taken generally along line 3--3 ofFIG. 2.

FIG. 4 is a simplified sectional view similar to FIG. 3 and showing asecond form of drive element.

FIG. 5 is a simplified sectional view similar to FIG. 3 showing a thirdform of drive element.

FIG. 6 is a simplified sectional view similar to FIG. 3 showing a fourthform of drive element.

FIG. 7 is a sectional view of a variable speed transmission constructedin accordance with the teachings of this invention and incorporatingtherein two transmission units.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1 and 2 show a variable speed transmission 11 which generallyincludes a housing 13 which forms a supporting structure of thetransmission, an outer rotatable member 15, an inner rotatable member17, a plurality of identical one-way clutches 19 mounted on, andconcentric with, the inner rotatable member, and a plurality of driveelements 21 pivotally attached to the one-way clutches 19, respectively,and to the outer rotatable member 15. Although the housing 13 could takedifferent forms, in the embodiment illustrated, it includes a housingsection 23 which may be comprised of one or more individual sections anda cover plate 25 suitably removable attached to the housing section 23as by a plurality of screws 27.

Although the outer rotatable member 15 may take different forms, in theembodiment illustrated, it includes a shaft 29 mounted on an end wall 31of the housing by a bearing 33. The shaft 29 projects through the endwall 31 and is suitably affixed to a suitable power transmission elementsuch as a sprocket 35. The outer rotatable member 15 also includes aradial wall 37 and a peripheral wall 39. The peripheral wall in theembodiment illustrated is cylindrical and coaxial with the shaft 29. Theradial wall 37 and the peripheral wall 39 may be integral, and in theembodiment illustrated, the inner end of the peripheral wall isrotatably mounted within the housing 13 by a bearing 41. Thus, thebearings 33 and 41 cooperate to mount the outer rotatable member 15 forrotational movement about a rotational axis 42 which is coincident withthe central axis of the member 15.

The rotatable member 15 is characterized herein as an outer rotatablemember even though not all portions thereof lie radially outwardly ofthe inner rotatable member 17. The rotatable member 15 is an outerrotatable member in the sense that the location of the attachments ofthe drive elements 21 to the rotatable member 15 lie radially outwardlyof the inner rotatable member 17. This attachment is accomplished in theembodiment shown in FIG. 2 by employing the peripheral wall 39; however,obviously other structural arrangements for attaching the drive elements21 to the rotatable member 15 radially outwardly of the rotatable member17 can be employed.

A mounting arm 43 is pivotally mounted on the housing 13 by a threadedfastener 45 and a sleeve bearing 47 (FIG. 2) mounted on the fastener.The mounting arm 43 pivots about a pivot axis 48 which is defined by thecentral axis of the screw 45 and which is parallel to the rotationalaxis 42.

The inner rotatable member 17 projects through, and is mounted on, themounting arm 43 by a pair of bearings 49. The bearings 49 mount theinner rotatable member for rotation about a rotational axis 50 which iscoincident with the central axis of the member 17 and which is parallelto the axis 42. The outer end of the inner rotatable member 17 extendsthrough an opening in the cover plate 25 and is suitably affixed to asuitable motion transmitting element such as a sprocket 51.

The one-way clutches 19 are mounted on the inner rotatable member 17 andare stacked in an axially extending row. Each of the one-way clutches 19is identical and is arranged to drive in one direction and free wheel inthe other direction. The one-way clutches 19 are arranged on the innerrotatable member 17 so that all of them drive in the same direction.Each of the one-way clutches 19 may be of the Sprag or roller type, eachof which has internal members which grip the inner rotatable member 17in the driving direction to form a driving connection between the clutchand the inner rotatable member and which allow free wheeling in theother direction to permit relative angular motion between the innerrotatable member and the clutch in the opposite direction.

In the embodiment illustrated in FIGS. 1-3, each of the drive elements21 is in the form of a rigid link pivotally coupled to flanges 53 on theone-way clutches 19 by pins 55. Although four of the drive elements 21are illustrated, any number may be provided depending upon the outputmotion desired. The flanges 53 on the one-way clutches 19 are spacedcircumferentially and, in the embodiment illustrated, are equally spacedcircumferentially when the axes 42 and 50 coincide. Because four of thedrive elements 21 are provided, the centers of the pivotal attachmentsbetween the drive element and the associated one-way clutch 19, i.e.,the center line of the associated pin 55 are spaced apart 90°.

Similarly, the outer ends of the drive elements 21 are pivotally coupledto the peripheral wall 39 of the outer rotatable member 15 by pins 57which extend through flanges 59 mounted on the peripheral wall. Thelocation of the attachments of the drive elements 21 to the peripheralwall 39, i.e., the center lines of the pins 57 are spaced apartcircumferentially equal distances which is 90° in the embodimentillustrated. In the embodiment illustrated, the axes of the pivotalattachments between the drive elements 21 and the clutches 19 and theperipheral wall 39 are parallel to the rotational axes 42 and 50.

The radial spacing between the rotational axes 42 and 50 can be variedby pivoting the mounting arm 43 about the pivot axis 48. This also movesthe inner rotatable member 17 along an arcuate path to bring about theadjustment in the radial spacing between the rotational axes 42 and 50.Various means, such as releasable detent means 61, are provided forreleasably fixing the mounting arm 43 and the inner rotatable member 17in any one of a plurality of positions along such path.

Although the releasable detent means 61 may take different forms, in theembodiment illustrated, it includes a stop element 63 affixed to thehousing section 21 and having a plurality of notches 65 therein openingtoward the mounting arm 43. A detent 67 is mounted in a passage 69 inthe outer end of the mounting arm 43 and is resiliently urged toward thenotches 65 by a spring 71. The cooperation between the detent 67 and aselected one of the notches 65 retains the mounting arm 43, and hencethe inner rotatable member 17, in the selected position relative to therotational axis 42.

A cam 73 extends through an opening 75 in the detent 67 and throughappropriate openings in the mounting arm 43 for the purpose ofselectively removing the detent 67 from interlocking engagement with thenotches 65. This allows the mounting arm 43 and the inner rotatablemember 17 to be pivoted about the pivot axis 48 to adjust the radialspacing between the rotational axes 42 and 50.

The cam 73 has a cam surface 77 and the detent 67 has a cooperating camfollower surface 79 opening into the opening 75. Movement of the cam 73is limited by flanges 81. The cam 73 can be moved in any suitable waysuch as rods or cables, and in the embodiment illustrated a rigidpush-pull rod is used. The rod 83 extends from a location outside thehousing 13 so that it can be appropriately manipulated, either manuallyor by a suitable mechanism (not shown).

By pulling the rod 83 downwardly as viewed in FIG. 1, the cam surface 77cooperates with the cam follower surface 79 to urge the detent 67inwardly of the mounting arm 43 against the biasing action of the spring71. When the tip of the detent 67 clears the notch 65 in which it hasbeen positioned, the mounting arm 43 pivots clockwise about the pivotaxis 48 because of the torque applied thereto by the pull of the rod 83.When the desired angular position of the mounting arm 43 has beenreached, the tension on the rod 83 is reduced to allow the spring 71 tourge the detent 67 into another one of the notches 65 to thereby fix themounting arm 43 and the inner rotatable member 17 in a new position. Bypushing the rod 83, the action described above can be repeated, exceptthat the mounting arm 43 will be pivoted counterclockwise about thepivot axis 48, i.e., moved upwardly as viewed in FIG. 1. The force ofthe spring 71 and the resistance of the mounting arm 43 to rotation canbe tailored so that withdrawal of the detent 67 from the notches 65 doesnot result in rapid pivoting of the mounting arm to an extreme position.

The transmission 11 can be used to transmit motion and power from thesprocket 35 to the sprocket 51 or from the sprocket 51 to the sprocket35. In other words, the outer rotatable member 15 may serve as eitherthe input member or the output member. Regardless of which of themembers 15 and 17 is the input, the transmission 11 will operate to stepup the motion, i.e., to provide a greater angular displacement at theoutput than at the input. The transmission 11 can be used to drive ineither direction, i.e., clockwise or counterclockwise; however, it isnecessary to arrange the one-way clutches 19 so that they will drive inthe desired direction.

The ratio of angular displacement at the input to angular displacementat the output can be varied by adjusting the radial spacing between therotational axes 42 and 50. When the rotational axes 42 and 50 arecoincident, the drive ratio is one to one and as the rotational axis 50is radially displaced from the rotational axis 42, the drive ratioincreases.

The radial spacing between the rotational axes 42 and 50 can beestablished as discussed above utilizing the rod 83. If the drive ratiois to be other than one to one, the arm 43 may be pivoted so as to movethe rotational axis 50 in either direction. Assuming that the innerrotational member 17 is the input member and is driven counterclockwiseas indicated by the arrow in FIG. 1, then the inner rotatable member 17applies a pulling force to the drive elements 21 to rotate the outerrotatable member 15 in the counterclockwise direction. Assuming that therotational axes 42 and 50 are not coincident, then each of the driveelements 21 will tend to pull the outer rotational member 15 at adifferent angular velocity depending upon the relative positions of thedrive elements about the rotational axis 50. The one-way clutch 19 forthe drive element 21 which is in a driving mode will provide a drivingconnection between the inner rotatable member 17 and the associateddrive element whereas the one-way clutches for the drive elements 21which are moving faster are in a free wheeling mode so as not to impedethe rotation of the outer rotatable member 15. When the outer rotatablemember 15 is the drive member the direction of motion is reversed, andthe one-way clutches 19 for the drive elements 21, which are movingslower than the driving element which is in the driving mode, are freewheeling.

Except for drive ratios of 1:1, the number of output pulses tending todrive the driven member is a function of the angular velocity of theouter rotatable member 15 and the number of drive elements 21. Forexample, with four drive elements 21 the outer rotatable member 15 asthe driven member, and a drive ratio of 1:2, there will be 8 outputpulses per revolution of the input member. Thus, by using the innermember 17 as the input, the number of output pulses increases with thedrive ratio.

FIG. 4 shows a transmission 11a which is identical to the transmission11 except for the manner in which the outer rotatable member 15a isdrivingly coupled to the inner rotatable member 17a. Portions of thetransmission 11a corresponding to portions of the transmission 11 aredesignated by corresponding reference numerals followed by the letter a.

The transmission 11a has drive elements 21a, and although for clarityonly one drive element is shown in FIG. 4, it should be understood thata plurality may be provided as shown, for example, in FIGS. 1-3. Thedrive element 21a is coupled by a pin 57a and flanges 59a to the outerrotatable member 15a. The drive element 21a has an opening 87 whichreceives a bearing 89 and an eccentric 91 mounted on a one-way clutch19a. The drive element 21a is a rigid link which circumscribes theeccentric 19 and the inner rotatable member 17a.

As discussed above, when the inner rotatable member 17a drives the outerrotatable member 15a, the approximate drive ratio is 1:1/1-X where X=A/Rand A is the amount of displacement of the axis of rotation of the innerrotatable member from the axis of rotation of the outer rotatable memberand R is the distance between the axis of rotation of the inner memberand the center of the location of attachment of the drive element to theinner member. To obtain a maximum drive ratio and the greatest ratiochange for an increment of relative displacement between the rotationalaxes of the rotatable members, the R dimension should be minimized. Oneadvantage of the embodiment of FIG. 4 is that the R dimension is verysmall, and accordingly these advantages are readily obtainable with theembodiment of FIG. 4. The transmission 11a operates in the same manneras described above with reference to the transmission 11.

FIG. 5 shows a transmission 11b which is identical to the transmission11 in all respects except for the manner in which a driving connectionis provided between the outer rotatable member 15b and the innerrotatable member 17b. Portions of the transmission 11b corresponding toportions of the transmission 11 are designated by correspondingreference numerals followed by the letter b.

The one-way clutch 19b has an outer peripheral surface 93. A flexibledrive element 21b in the form of a cable is attached at one end to theflange 59b and at the other end to the flange 53b of the one-way clutch19b. The flexible drive element 21b extends over and engages a portionof the peripheral surface 93. To maintain the drive element 21b taut, acoil spring 95 is attached at one end to the outer rotatable member 15band at the other end to a cable 97 which in turn is attached to theone-way clutch 19b. As with the transmission 11, as many of the one-wayclutches and drive elements as may be desired can be employed dependingupon the desired linearity of the output.

The transmission 11b operates in the same manner as described above withreference to transmission 11. However, the cable is lighter and takesless room than the rigid link type of drive element. In addition, theperipheral surface 93 can be shaped to provide some additional controlover the nature of the output motion. For example, in the embodimentillustrated, the peripheral surface 93 is noncylindrical andconstitutes, in effect, a cam which tends to make the output motion morelinear. The noncylindrical peripheral surface 93 may be integral withthe one-way clutch 19b, or it may be provided by a suitably configuredsleeve mounted on the one-way clutch.

FIG. 6 shows a transmission 11c which is identical to the trannsmission11 except for the manner in which the outer rotatable member 15c isdrivingly coupled to the inner rotatable member 17c. Portions of thetransmission 11c corresponding to portions of the transmission 11 aredesignated by corresponding reference numerals followed by the letter c.

In the transmission 11c, the drive element 21c is in the form of a chainwhich is pivotally attached at one end to the outer rotatable member 15cby a pin 57c to a flange 59c and attached at its opposite end by aspring 95c to the outer rotatable member. In the embodiment illustrated,the pin 57c and the location of the attachment of the spring 95c to theouter rotatable member 15c are spaced apart 180°; however, obviouslyother spacings are permissible. The one-way clutch 19c has an outerperipheral surface which defines teeth 99 adapted to drivingly engagethe chain and an intermediate portion of the chain is so engaged by theteeth. The teeth 99 may be arranged in a cylindrical or noncylindricalpattern, and in this latter event, a camming action which affects thelinearity of the output motion is obtained. The spring 95c maintains thechain 21c taut.

The transmission 11c operates in the same manner described above withreference to the transmission 11. The advantages noted above for thetransmission 11b are also applicable to the transmission 11c.

FIG. 7 shows a transmission 101 which comprises two transmission units103 and 105 drivingly interconnected by a shaft 107. The transmissionunits 103 and 105, in the embodiment illustrated, are substantiallyidentical and may conform to any of the transmissions 11, 11a, 11b, and11c. In the embodiment illustrated, the transmission units 103 and 105conform to the transmission 11 and portions thereof are designated bycorresponding primed reference numerals. The housings 13 of thetransmission units 103 and 105 are suitably interconnected as by screws109 and the mounting arm 43' is mounted therebetween on roller bearings111 and a fastener 45' for a pivotal movement about a pivotal axis 48'.

In the embodiment illustrated, both of the inner rotatable members 17are coupled to, or integral with, the shaft 107. The shaft 107 is inturn rotatably mounted by bearings 49' on the mounting arm 43'.Accordingly, by pivoting the mounting arm 43', both of the innerrotatable members 17' are simultaneously displaced radially the sameamount relative to their associated outer rotatable members 15'.

The transmission 101 may be operated in the same manner as thetransmission 11. For example, assuming that the sprocket 35' is thedrive member, then the outer rotatable member 15' of the transmissionunit 103 drives the inner rotatable member 17' as previously described.This rotates the shaft 107 to drive the inner rotatable member 17' ofthe transmission unit 105. The inner rotatable member 17' of the driveunit 105 drives the associated outer rotatable member 15' and thesprocket 51'. Thus, the transmission unit 103 drives from the outermember to the inner member, and the transmission unit 105 drives fromthe inner member to the outer member. Both of the transmission units 103and 105 operate to step up the motion and the overall drive ratio of thetransmission 101 is greater than twice the drive ratio of thetransmission unit 103 and less than twice the drive ratio of thetransmission unit 105. The mounting arm 43' and the inner rotatablemember 17' can be moved in the manner described above with reference tothe transmission 11. The transmission units 103 and 105 may be coupledtogether in other ways so that, for example, the outer rotatable memberof one would drive the inner rotatable member of the other, or the outerrotatable member of one would drive the outer rotatable member of theother.

Although exemplary embodiments of the invention have been shown anddescribed, many changes, modifications and substitutions may be made bythose having ordinary skill in the art without necessarily departingfrom the spirit and scope of this invention.

I claim:
 1. A variable speed transmission comprising:first and secondrotatable members; .Iadd.first .Iaddend.mounting means for mounting saidfirst .[.and second.]. rotatable .[.members.]. .Iadd.member .Iaddend.forrotation about .Iadd.a .Iaddend.first .[.and second.]. rotational.[.axes, respectively.]. .Iadd.axis.Iaddend.; .Iadd.second mountingmeans for mounting said second rotatable member for rotation about asecond rotational axis; .Iaddend. at least one drive element; firstmeans for drivingly coupling the drive element to the first rotatablemember; second means for drivingly coupling the drive element to thesecond rotatable member at a predetermined location; said first meansincluding one-way clutch means mounted on and substantiallycircumscribing the first rotatable member for providing a drivingconnection between said drive element and the first rotatable member inone direction about said first rotational axis and to allow the firstrotatable member to rotate about said first rotational axis in theopposite direction whereby one of said rotatable members can drive theother of said rotatable members; the rotation of said second rotatablemember causing said predetermined location to circumscribe a region,said first rotational axis extending through said region; .[.and.]..Iadd.at least one of .Iaddend.said mounting means including means forallowing adjustment in the relative radial position of said rotationalaxes whereby the drive ratio between said members can be varied.Iadd.;and said first mounting means supporting said first rotatable member onone side of said one-way clutch means and said first rotatable memberbeing unsupported on the other side of said one-way clutch means andradially inwardly of said one-way clutch.Iaddend..
 2. A variable speedtransmission as defined in claim 1 wherein said drive element includes aflexible drive element drivingly coupled to said rotatable members andresilient means for tensioning said flexible element.
 3. A variablespeed transmission as defined in claim 1 wherein said drive elementincludes a rigid link and said second means pivotally connects said linkand said second rotatable member.
 4. A variable speed transmission asdefined in claim 3 wherein said first means includes an eccentriccoupled to said one-way clutch means, said link at least substantiallycircumscribing said eccentric and bearing means between said eccentricand said link for providing a connection therewith which allows relativemovement between said link and said eccentric.
 5. A variable speedtransmission as defined in claim 1 wherein the first rotatable memberdrives the second rotatable member through said drive element and saiddrive ratio can have a value such that the angular velocity of thesecond rotatable member exceeds the angular velocity of the firstrotatable member, the number of pulses of the motion of the secondrotatable member being a function of the angular velocity of the secondrotatable member.
 6. A variable speed transmission as defined in claim 1wherein said adjustment means moves the first rotatable member and saidone-way clutch means to adjust the relative radial position of saidrotational axes.
 7. A variable speed transmission comprising:outer andinner rotatable members; .Iadd.first .Iaddend.mounting means formounting said outer .[.and inner.]. rotatable .[.members.]. .Iadd.member.Iaddend.for rotation about .[.said.]. .Iadd.a .Iaddend.first .[.andsecond.]. rotational .[.axes, respectively.]. .Iadd.axis.Iaddend.; atleast first and second one-way clutches mounted on and substantiallycircumscribing said inner rotatable member, said first and secondone-way clutches being arranged on said inner rotatable member in anaxially extending row; .Iadd.second mounting means for supporting theinner rotatable member on one side of said row of one-way clutches forrotational movement about a second rotational axis whereby the innerrotatable member is unsupported on the other side of said row of one-wayclutches and radially inwardly of said row of one-way clutches;.Iaddend. first and second drive elements attached to said first andsecond clutches, respectively, at circumferentially spaced locations andattached to said outer rotatable member at circumferentially spacedlocations whereby rotation of one of said members about its rotationalaxis causes said drive elements to rotate the other of said rotatablemembers about its rotational axis; and .Iadd.at least one of.Iaddend.said mounting means including means for permitting adjustmentof the radial spacing between said rotational axes.
 8. A variable speedtransmission as defined in claim 7 said outer member includes aperipheral wall substantially circumscribing said first and secondone-way clutches.
 9. A variable speed transmission as defined in claim 7wherein said adjustment means includes means for mounting said innerrotatable member for pivotal movement about a third pivotal axisradially spaced from said first rotational axis whereby pivotal movementof said inner rotatable member about said third axis adjusts the radialspacing between said first and second rotational axes.
 10. A variablespeed transmission as defined in claim 7 wherein said adjustment meansincludes means for mounting said inner rotatable member for movementalong a path in a direction to adjust the radial spacing between saidfirst and second rotational axes and releasable detent means forreleasably fixing said inner member in any one of a plurality ofpositions along said path.
 11. A variable speed transmission as definedin claim 10 wherein the releasable detent means includes a detentmovable with said inner member, a stop element having a plurality ofnotches therein, means for mounting said stop element in a fixedposition, resilient means for urging said detent into any one of saidnotches to thereby releasably fix the relative positions of said firstand second rotational axes, and means for selectively removing thedetent from an associated one of the notches whereby the inner rotatablemember can be moved along said path.
 12. A variable speed transmissionas defined in claim 7 wherein said outer and inner rotatable members arefirst outer and inner rotatable members, respectively, and including asecond outer rotatable member and a second inner rotatable member,.[.second.]. .Iadd.third .Iaddend.mounting means for mounting saidsecond outer and second inner rotatable members for rotation about thirdand fourth rotational axes, respectively, at least third and fourthone-way clutches mounted on said second inner rotatable member;third andfourth drive elements attached to said third and fourth clutches,respectively, at circumferentially spaced locations whereby the rotationof one of said second rotatable members about its rotational axis causessaid third and fourth drive elements to rotate the other of said secondrotatable members about its rotational axis, said .[.second.]..Iadd.third .Iaddend.mounting means including means for permittingadjustment of the radial spacing between said third and fourthrotational axes, and means for coupling one of said first rotatablemembers to one of said second rotatable members.
 13. A variable speedtransmission comprising:a housing; first and second variable speedtransmission units in said housing; each of said transmission unitsincluding outer and inner rotatable members, mounting means for mountingsaid outer and inner rotatable members for rotation about first andsecond rotational axes, respectively, at least one one-way clutchmounted on said inner rotatable member, a first drive element attachedto said one-way clutch and to said outer rotatable member whereby therotation of either of said rotatable members about its rotational axiscauses the drive element to rotate the other of said rotatable membersabout its rotational axis, said mounting means including means formounting one of said rotatable members for movement along a path topermit adjustment of the radial spacing between said rotational axes tothereby change the drive ratio; and means for drivingly coupling saidone rotatable member of the first transmission unit to said onerotatable member of the second transmission unit whereby one of saidtransmission units can drive the other of said transmission units andthe drive ratios of both of the transmission units can be simultaneouslychanged.
 14. A variable speed transmission as defined in claim 13wherein the members coupled by said coupling means are said innerrotatable members.
 15. A variable speed transmission comprising firstand second rotatable members;mounting means for mounting said first andsecond rotatable members for rotation about first and second rotationalaxes, respectively; at least one flexible drive element; first means fordrivingly coupling the flexible drive element to the first rotatablemember; second means for drivingly coupling the flexible drive elementto the second rotatable member at a predetermined location; at least oneof said first and second means including a one-way clutch whereby one ofsaid rotatable members can drive the other of said rotatable membersthrough said flexible drive element; the rotation of said secondrotatable member causing said predetermined location to circumscribe aregion, said first rotational axis extending through said region; saidmounting means including means for allowing adjustment in the radialspacing between said rotational axes whereby the drive ratio betweensaid members can be varied; and resilient means for tensioning theflexible drive element.
 16. A variable speed transmission as defined inclaim 15 wherein said flexible drive element includes a chain drivinglycoupled by said second means to said second rotatable member and saidfirst means includes sprocket teeth cooperable with said chain to form adriving connection therewith.
 17. A variable speed transmission asdefined in claim 15 including means on said first rotatable memberdefining a noncylindrical peripheral surface, said flexible driveelement extending along and engaging at least a portion of saidnoncylindrical surface. .Iadd.18. A variable speed transmission asdefined in claim 7 wherein said outer rotatable member has a peripheralwall substantially circumscribing said first and second one-way clutchesand an end wall on said other side of said row of one-way clutches andsaid inner rotatable member terminates short of said end wall. .Iaddend..Iadd.19. A variable speed transmission as defined in claim 7 whereinsaid adjustment means includes a mounting arm and means for mounting themounting arm for pivotal movement about a third axis which is radiallyspaced from said second rotational axis and said second mounting meansmounts said inner rotatable member on said mounting arm whereby pivotalmovement of the mounting arm about said third axis adjusts the radialspacing between the first and second rotational axes. .Iaddend..Iadd.20. A variable speed transmission as defined in claim 19 whereinsaid outer rotatable member has a peripheral wall substantiallycircumscribing said first and second one-way clutches and an end wall onsaid other side of said row of one-way clutches and said inner rotatablemember terminates short of said end wall. .Iaddend. .Iadd.21. A variablespeed transmission comprising:outer and inner rotatable members; firstmounting means for mounting said outer rotatable member for rotationabout a first rotational axis; second mounting means for mounting saidinner rotatable member for rotation about a second rotational axis; atleast first and second one-way clutches mounted on and substantiallycircumscribing said inner rotatable member, said first and secondone-way clutches being arranged on said inner rotatable member in anaxially extending row; first and second drive elements attached to saidfirst and second clutches, respectively, at circumferentially spacedlocations and attached to said outer rotatable member atcircumferentially spaced locations whereby rotation of one of saidmembers about its rotational axis causes said drive elements to rotatethe other of said rotatable members about its rotational axis; at leastone of said mounting means including means for permitting adjustment ofthe radial spacing between said rotational axes; and said outerrotatable member having an end wall on one side of said row of one-wayclutches, said inner rotatable member and said second mounting meansterminating short of said end wall. .Iaddend. .Iadd.22. A variable speedtransmission comprising:first and second rotatable members; firstmounting means for mounting said first rotatable member for rotationabout a first rotational axis; second mounting means for mounting saidsecond rotatable member for rotation about a second rotational axis; atleast one drive element; first means for drivingly coupling the driveelement to the first rotatable member; second means for drivinglycoupling the drive element to the second rotatable member at apredetermined location; said first means including one-way clutch meansmounted on and substantially circumscribing the first rotatable memberfor providing a driving connection between said drive element and thefirst rotatable member in one direction about said first rotational axisand to allow the first rotatable member to rotate about said firstrotational axis in the opposite direction whereby one of said rotatablemembers can drive the other of said rotatable members; the rotation ofsaid second rotatable member causing said predetermined location tocircumscribe a region, said first rotational axis extending through saidregion; at least one of said mounting means including means for allowingadjustment in the relative radial position of said rotational axeswhereby the drive ratio between said members can be varied; and saidsecond rotatable member having an end wall and at least partiallyreceiving said first rotatable member, said first rotatable member andsaid first mounting means terminating short of said end wall. .Iaddend..Iadd.23. A variable speed transmission comprising:outer and innerrotatable members; mounting means for mounting said outer and innerrotatable members for rotation about said first and second rotationalaxes, respectively; at least first and second one-way clutches mountedon and substantially circumscribing said inner rotatable member, saidfirst and second one-way clutches being arranged on said inner rotatablemember in an axially extending row; first and second drive elementsattached to said first and second clutches, respectively, atcircumferentially spaced locations and attached to said outer rotatablemember at circumferentially spaced locations whereby rotation of one ofsaid members about its rotational axis causes said drive elements torotate the other of said rotatable members about its rotational axis;said mounting means including means for permitting adjustment of theradial spacing between said rotational axes; and said adjustment meansincluding means for mounting said inner rotatable member for pivotalmovement about a third pivotal axis radially spaced from said firstrotational axis whereby pivotal movement of said inner rotatable memberabout said third axis adjusts the radial spacing between said first andsecond rotational axes. .Iaddend. .Iadd.24. A variable speedtransmission comprising:outer and inner rotatable members; firstmounting means for mounting said outer rotatable member for rotationabout a first rotational axis; second mounting means for mounting saidinner rotatable member in cantilever fashion for rotation about a secondrotational axis whereby a length of said inner rotatable member fromsaid second mounting means through a first end of said inner rotatablemember is unsupported; at least first and second one-way clutchesmounted on and substantially circumscribing said length of said innerrotatable member, said first and second one-way clutches being arrangedon said length of said inner rotatable member in an axially extendingrow; first and second drive elements attached to said first and secondclutches, respectively, at circumferentially spaced locations andattached to said outer rotatable member at circumferentially spacedlocations whereby rotation of one of said members about its rotationalaxis causes said drive elements to rotate the other of said rotatablemembers about its rotational axis; and at least one of said mountingmeans including means for permitting adjustment of the radial spacingbetween said rotational axes..Iaddend.